The present invention relates generally to a vent control system and, more particularly, to a closed biased vent valve used in a fuel vapor separator.
Vent valves are used in a variety of applications to remove vapor or air from a liquid in a container. The typical vent valve operates to expel the vapor as the fluid enters the vessel, thereby allowing the fluid to enter the vessel without being restricted by vapor within the vessel. Some of these systems are not required to be pressurized. The venting arrangement for these unpressurized systems can be as simple as an open vent line located on the top of the vessel. Other unpressurized systems may have a check valve in the vent line to prevent return vapor flow into the vessel, and still other systems may have a vapor recovery system to return the fluid vapors back to the vessel while expelling vapor. Pressurized systems must incorporate measures to expel air or vapor via a venting system that allows the vessel to become pressurized after venting. Vent valves used in pressurized systems typically include a needle and seat arrangement wherein the needle is operated by a float assembly to engage and disengage a stationary seat at the top of the vessel. When the vessel is empty, or the fluid level in the vessel is low, the float pulls the needle into an open position to allow venting. As the fluid fills the vessel, the float moves upward and closes the needle against the seat.
One application for vent valves or vapor release valves is in fuel vapor separators. Fuel vapor separators are often used in fuel delivery systems of internal combustion engines to remove entrained vapor from fuel. Heat in an engine can adversely affect the engine""s fuel delivery system by causing fuel to vaporize before it is introduced into the engine""s combustion chamber. The vaporized fuel interferes with proper engine combustion and, consequently, with engine power and performance. Fuel vapor separators are used for reducing or eliminating vaporized fuel in the fuel delivery system. The typical fuel vapor separator includes a housing through which fuel passes and in which vapor is allowed to separate from the fuel. The fuel vapor is vented from the fuel vapor separator through a vent valve, which is usually of a movable needle and stationary seat type that is operated by a float assembly as previously described. After venting is complete, the vent valve closes upon consequent filling of the fuel vapor separator with fuel and the resultant upward float movement.
Float operated vent valves can open prematurely in some systems which lead to unintended venting of liquid from the associated chamber. For instance, outboard marine engines are subjected to oscillations and vibrations when the boat is driven over turbulent waves. These oscillations and vibrations can cause the float in the engine""s fuel vapor separator to bounce, leading to unintended opening of the vent valve, which allows fuel to vent and potentially flood the engine. Therefore, it would be desirable to design a vent valve that combats unintended or premature vent valve opening.
The present invention solves the aforementioned problems by providing a vent control system that has a closed biased vent valve. The invention includes a float having an upwardly extending float arm and a lever arm, which selectively disengages from one another upon unwanted float movement within a chamber to prevent unintended release of vapor or fuel from the chamber. This vent control system is much less susceptible to vibration induced vent opening than a traditional vent valve and significantly reduces engine sputtering caused by fuel entering the engine through the vent system, which is often referred to as xe2x80x9cengine spitxe2x80x9d.
In accordance with another aspect of the invention, a vent control system for a fuel vapor separator includes a housing that has an enclosed fuel chamber and a fuel float having an upwardly extending float arm located in the enclosed fuel chamber. A lever arm, connected to a closed biased vent valve, is coupled to the float arm such that the float arm and the lever arm are configured to decouple from one another when the float rises to a certain level within the fuel chamber.
In accordance with another aspect of the invention, a method is provided for reducing engine spit. The method includes transferring fuel into an enclosed fuel chamber from at least one fuel injector through a plurality of fuel inlet ports and venting vapor accumulating within the enclosed chamber via selective opening of a closed biased vent valve. A method further includes allowing flow movement vertically without opening the closed vent valve within the enclosed fuel chamber thereby reducing engine spit caused by unintended opening of the closed biased vent valve due to engine vibration.
In accordance with yet another aspect of the invention, a means is provided for transferring fuel into an enclosed fuel chamber from a fuel source and venting vapor that is accumulated within the enclosed fuel chamber via selective opening of a closed biased vent valve. A means is also provided for allowing float movement vertically without opening the closed biased vent valve, thereby reducing engine spit caused by unintended opening of the closed biased vent valve due to the engine vibration.
Various other features, objects and advantages of the present invention will be made apparent from the following detailed description and the drawings.